Mechanical stresses can occur during operation of the piezoactuator, as a result of which cracks can arise. In particular, such stresses occur in the boundary region between so-called active zones and inactive zones, in which the piezoelectric layers expand to different extents. In order that cracks do not arise in an uncontrolled fashion in the stack and thus cause, for example, a short circuit between electrode layers of different polarities, the stacks are provided with predetermined breaking layers. The predetermined breaking layers are embodied such that cracks occur particularly easily in the predetermined breaking layers and propagate within the predetermined breaking layers.
The PCT document WO 2004/077583 A1 describes a piezoactuator having predetermined breaking layers.